As a container formed of resin, there is known one having a configuration disclosed in Patent Document 1 for instance. In this, in a PET bottle having a relatively large inner contents capacity of 2 liters approximately, for facilitating a consumer's gripping of the bottle at the time of drinking, adjacent vertical center portions of a body portion, there are provided concave portions on which the consumer can places the thumb and the middle finger (or the index finger), respectively for gripping.
On the other hand, in recent years, with increasing awareness of environmental problems, weight reduction has been aggressively promoted for containers formed of resin also.